Why the surge? It’s likely that investors bought into Amazon CEO Jeff Bezo’s Kindle device strategy. “We want to make money when people use our devices, not when they buy our devices,” Bezos said during today’s press conference.

So far the strategy has been an effective one, allowing Amazon’s Kindle Fire to claim 22 percent of the tablet market since last year. That trend is likely to continue with the latest set of Kindle Fire tablets, which improve on the formula heralded by the original.